Airplane propeller and process of making the same



Julie 16, 1925.

- w. A. LORENZ ET AL AIRPLANE PROPELLER' AND PROCESS OF MAKING THE sum Filed April 20, 1921 2 sheets-Shut 1 'Jum: 16, 1925.

. w. A. LORENZ ET AL AIRPLANE PROPELLER ANDPHOCESS OF MAKING THE SAIIE 2 Sheets-Shoot 2 Filed April 20, 1921 j iy. F

Patented June 16, 1925.

STATES PATENTT OFFICE.

WILLIAM A.

LORENZ AND STILLMAN SHAW, F HARTFORD, CONNECTICUT; SAID SHAW ASSIGNOR OF HIS ENTIRE RIGHT TO SAID LORENZ.

AIRPLANE PROPELLER AND PROCESS O1 MAKING THE SAME. i

A ncaumimea April 20, 1921. Serial No. 462,795.

To all whom it may concern:

Be it known that we, WILLIAM A. LORENZ and STILLMAN SHAW, citizens of United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented new and useful Improvements in Airplane Propellers and Processes of Making the Same, of which the following is a Specification.

This invention consists in an improvement in the method of making airplane propellers and consists in cutting or shaping the propeller from vulcanized fiber which has been chemically treated and washed, and is still wet and pliable; then perforating the soft liber edgewise, and twisting the blades to the helical pitch desired, while in a soft condition, and their drying the propeller and varnishing the same after drying.

In the drawings Figure 1 represents a plan view and Fig. 2, an end View, of a block of vulcanized fiber which has been chemically treated and has been washed, and is in a soft condition. Fig. 3 shows a plan view, and Fig. 4 a sectional view on the line 4:& of Fig. 3, of a propeller which has been approximately carved to shape while in a soft condition. It is then perforated edgewise. Fig. 5 shows an edge 30 view of Fig. 3, and Fig. 6 shows a sectional view of Fig. 3 on the line 66, of the propeller after cutting to shape and perforating. Fig. 7 shows the propeller of Fig. 3, with its blades twisted. Fig. 8 shows the propeller of Fig. 5 with its blades twisted. Fig. 9 shows a plan View of the apparatus for holding the twisted propeller of Fig. 8, while drying. Figs. 10, 11 and 12 show sectional views through lines 1O1(), 1111 and 'i2--12, respectively, of Fig. 9. Figs. 13 and 14L show, respectively, a plan view and an end View of the means for clamping the propeller to a central hub, which may be attached to the driving shaft of an engine.

In making this propeller I proceed in the following manner A solid block of fibre is chemically treated with chloride of zinc and it is then washed to remove the zinc chloride therefrom. lVhile the solid block is in a soft and pliable condition, it is carved so as to form a solid hub portion and a pair of wings or blades which taper down towards their edges. Fig. 6 shows the edgewise punching of the blocks of Figs. 1 and 2, which is performed in the direction ofthe arrow15, making a hole 16 edgewise through the block, spreading the fiber in hub form, as shown at 17-,1?. I The two blades of the propeller areapproximately carved to shape, as in Figs. 3, l and 5, at19 and 20. The edges are made thin as shown at 21 and 22.

The propeller is then placed in a holding or drying fixture, as in Figs. 9, 10, 11 and 12, the blades being twisted and held by suitable clamps. A stud 25 is passed through the hole 16 of the propeller, and is heldin the fixture, at 26 and 27. The fiX ture is preferably provided with a series of sliding clamps 28, with cap pieces 29 and bolts 30; these clamps slide in the dovetailed groove of the bottom 32 of the fixture. A series of these clamps is employed on both sides of the stud 25, which clamps are so shaped as to twist the blades'to the heliX desired. The clamps are shown in Fig. 11, on the line ll11 of Fig. 9; in Fig. 12, on the line 12-12 of Fig. 9; and the central part of the holder is shown in Fig. 10, on the line 1.010 of Fig. 9. A section of the blade is shown at 35 in Fig. 10; at 36 in Fig. 11, and at 37 in Fig. 12. As the fiber shrinks while driving, the clamps will slide toward the central part of the fixture.

The propeller may be mounted in a hub 40, attached to the shaft 42 of the engine.

The advantage of forming the propeller in the manner described, in which a hole is punched edgewise through the material, is that it enables the propeller to be twisted in helical form, close to the hub, so that the propelling action takes place closer to the hub than is possible with a wooden propeller, having a flatted hub.

I claim as my invention:

1.. The process of forming a propeller for airplanes which consists in providing a solid block of fibrous material, chemically treating the block and then washing the same, carving the block while it is still moist and pliable so as to form a hub and solid blades which are tapered down towards their edges, then twisting the blades to the helical pitch desired while in soft and pliable condition, and then drying the propeller while it is held in twisted condition.

2. The process of forming a propeller of vulcanized fibre which consists in providing a solid block of fibre, treating the block with chloride or zinc, the!) Washing the zinc chloride from the block, then carving the block to form a hub and solid blades, then, while the carved block is in soft and pliable condition, twisting the blades approximately to the helical pitch desired, and then drying the propeller while the blades are held in twisted condition.

3. A propeller made from vulcanized fiber or similar material, having a. hub at its central portion, the hub being perforated edgewise through the fiber, and having wings or blades extending from the hub, said blades being twisted helically to the form desired, said helical twisting starting close to the perforated hole.

4. The combination of a propeller made from vulcanized fiber,- or similar material, having its central portion perforated edgewise, and having wings 0r blades helically twisted to the form of the propeller desired, the whole being dried and varnished, in combination with a hub to which the propeller is fastened, with means to-secure said hub to the shaft of an engine.

The herein-described process of mal .ing an airplane propeller, comprising shaping the propeller from vulcanized fiber which I has been chemically treated and "washed and is still wet andpliable 'thenperforating the soft'fiber edgewise, and twisting the blades to the helical pitch desired while in soft condition;

6. Theherein-described process o'l making an airplane propeller, comprising shaping the propeller froni vulcanized fiber which has been chemically treated and washed and is still wet and pliable; then perforating the soft fiber edgewise, twisting the blades to the helical pitch desired while in soft condition, and then drying'the propeller.

7. The herein-described process of making an airplane propeller, comprising shaping the propeller lroni vulcanized fiber which has been chemically treated and washed and is still wet and pliable; then perforating the soft fiber edgewise, twisting the blades to thehelical pitch desired while in soft condition, then drying the propeller, and varnishing the same after drying.

Signed at Hartford, Connecticut, this 18th day of April, 1921.

\VILLIAM A. LORENZ. STILI 1M A N SHAJV. Witnesses M. A. ZEISER, Crraams H. STORRS. 

